The Research On Ecological Adaptability To Water Stress Of Pinus Sylvestris Var.Mongolica

linus sy]vestris var. i~ongo1ica aged from 10 to 15 were used as materials, whose ecophysiological characteristics such as photosynthesis rate and transpiration rate were measured under different water stress in Huhhot suburb of semirought areas. furthermore, its responses and ecological adaptability to water stress were studied and concluded at different annual growth periods. resaturated relative water content(RSRWC) declined., but the change was less and less. The tendency can be described as Y=K0XEXP (?B1 XX) (X was resaturating water saturation deficit(RSWSD), Y was resaturated relative water content (RSRWC)). (2) Water stress affected photosynthesis of linus sy]vestris var. fflongolica. With the increase of water stress, net photosynthesis rate declined, but the change was less and less . The tendency can be described as Y B0 + B1 X EXP (XX ) ( X was water saturation deficit ( WSD ) , Y was net photosynthesis rate ( 11 mol.nf2.s? ). (3)Inward water stress affected transpiration of linus sylvestris var. IDongolica. With the increase of water stress, transpiration rate declined, but the change was less and less. The tendency can be described as Y=K/ ( 1+B0 X EXP ( 1 X X)) (X was WSD, Y was transpiration rate ( mmol.n12.s1 ) ). (4)The adaptability to water stress of linus sylvestris var. mongolica. s was by decreasing transpiration in the growth period of young swigs, while it endured drought by maintaining turgor and metabolism ability ,and improving the ability to conserve water through increasing elasticity of cells. (5) At the flourishing period of June and July, linus sy]vestris var. ILngo]ica whole ossotoc potential at the turgor Inntlal loss point Is rather high, which is from—1．6 to－1．SMpa,and so its drought—resistance ability was weak．However,at the end of growth period,rznus SNvestrts ar mongo／二ca's shole osmotlc potential at turgor Inntlal loss point nas low．Therefore,ets drought－ressstance ability was such higher．The result provided theoretical proof for water utlllzatlon during afforestataon and management practice．...